JPS641645B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic latch adjuster used in a valve mechanism of a four-stroke engine.

The hydraulic lash adjuster is being used in various four-stroke engines because it enables zero lash operation of the valve train, quiet operation, and maintenance-free operation. By the way, when this hydraulic lash adjuster (hereinafter abbreviated as lash adjuster) is used in a parallel multi-cylinder engine, a single cylinder engine, or a V-type engine in which the cylinder portion is oriented upward, a problem may arise. However, in the case of an engine in which the cylinder part is installed horizontally, such as a horizontally opposed engine, or an engine installed at a near-horizontal inclination, the lash adjuster will be oriented sideways or downwards, causing this problem. As a result, the oil in the high pressure chamber that applies a static pressure reaction force to the slidably built-in plunger leaks out, making it impossible to function as a lash adjuster.

In order to avoid the above-mentioned problems, a structure has been considered in which the engine remains horizontal and the lash adjuster is mounted upright or at a slight incline within a range that does not cause any problems. In this structure, as shown in FIGS. 1 to 4, the axis _O2 of the rocker arm support portion 1a of the rocker arm shaft 1 is eccentric by h with respect to the center _O1 of the rocker arm shaft 1, The Rotsuker arm 2 is this Rotsuker arm support portion 1a.
(i.e., the eccentric part), and the non-eccentric part 1b
Zero lash is performed by the lash adjuster 4 that engages with the engaging recess 1c provided in the latching position. That is,
To perform an operation without creating a gap at a contact part between a cam 5 and a rocker arm 2. The head 4b of the plunger 4a of the lock adjuster 4 was formed into a spherical shape.

In the conventional structure as described above, the contact between the latch adjuster 4 and the engagement recess 1c of the rocker arm shaft 1 is limited to the bottom of the latch adjuster 4 (i.e., the body 4c) on the side of one valve, e.g., the exhaust valve 6. (1) A lash adjuster with a bottom 4d contact type. 4(A)
Since the head 4b of the plunger 4a is spherical, this head 4b makes point contact with the plug 8 as shown in FIG. 3, which is not advantageous in terms of durability in terms of wear. (2) Head 4b contact Model latching adjuster 4(B)
Since the plunger head 4b contacts the engagement recess 1c of the rocker arm shaft 1, the engagement recess 1c of the latch adjuster 4(B) has a substantially spherical shape as shown in FIG. As shown in the figure, the movement of the plunger 4a exerts a force in the direction of arrow A, which impairs the smoothness of mutual sliding between the plunger 4a and the latch adjuster body 4c. (3) Since the rocker arm 2 rotates, it is necessary to provide a member to receive the axial thrust of the rocker arm shaft 1, which increases costs. There are disadvantages such as being an element of

This invention was made in view of the above circumstances,
A plunger cap is detachably provided on the plunger head of a hydraulic latch adjuster, and is inserted into a mounting hole formed in a mounting member so that the outer peripheral surfaces of the body and the cap slide into contact with the inner peripheral surface of the mounting hole. This is an attempt to eliminate the above-mentioned drawbacks.

An embodiment in which the present invention is applied to a horizontally opposed engine of a motorcycle will be described below with reference to FIG. 5 and subsequent figures.

FIG. 5 is an exploded perspective view of the cylinder head portion. 10 shows the entire cylinder head of one horizontally opposed engine, and the other part shows each disassembled part of the cylinder head of the other engine. 11 is a cylinder head, 12 is a cam holder as a mounting member to which a latching adjuster 37 to be described later is attached, 13 is a cylinder head cover,
14 is the head gasket, 15 is the camshaft of the cylinder head 10, and 16 is the cylinder head 11.
camshaft, 17 is Rotsuker arm shaft, 18 is Rotsuker arm, 19 is oil seal, 20 is Rotsuker arm side spring, 2
1 is a valve holder, 22 is a valve spring retainer, 23 is a valve outer spring, 24 is a valve inner spring, 25 is a valve spring seat, 26 is an intake valve, 27 is an exhaust valve, 28 is a valve stem seal, 29 is an exhaust valve guide, 30
is the intake valve guide, 31 is the cylinder head gasket, 32 is the oil control orifice, 33
is a dowel pin. Further, 34 is a bolt for fixing the cylinder head 11 to a cylinder block (not shown), and 35 is a bolt for fixing the cam holder 12 to the cylinder head 11.
Bolts 36 are bolts that fix the cylinder head cover 13 to the cylinder head 11.

The details of the cam holder 12 and the parts attached thereto will be explained with reference to FIG.
The cylinder head 11 is rotatably supported by a semicircular pedestal formed in the cylinder head 11. The cam holder 1
2, the four rocker arms 18, four hydraulic latch adjusters 37, etc. are attached.

The Rotzker armshaft 17 is shown in Fig. 7A,
b. As shown in FIG.
7a and the axis of the small diameter portion 17b) It has a rocker arm support part 17c which is eccentric by h with respect to _O1 and has an axis _O2 , and both ends are fitted into holes 12a and 12b made in the cam holder 12. and is supported. Note that collars 38(A), 38(B), and 38(E) having the same outer diameter as the large diameter portion 17a are fitted into the small diameter portion 17b, and the small diameter portion 17b is connected to the hole 12 through the collar 38.
a or 12b. In addition, color 38
(C) and 38(D) are for preventing the rocker arm shaft 17 from coming off, and have the same outer diameter as the large diameter portion 17a. The collars 38(A) and 38(B) are the collar 38
Same as (C) and 38(D), Rotsuker armshaft 17
It also serves as a stopper. Color 38(A), 38(B)
The collars 38(C), 38 are connected by bolts 35(a) (only one location is shown) passed through the through holes 38a.
(D) and 38(E) are each fixed to the cam holder 12 by bolts 35(b) (only one location is shown) which are also passed through the through hole 38a. Note that 38b is a groove for adjusting the angle by turning with a screwdriver during setting. Further, the groove 17d on the end face of the rocker arm shaft 17 is also a groove for inserting a driver for adjusting the angle during setting. The rocker arm 18 is rotatably fitted into the rocker arm support portion 17c.

The latch adjuster 37 is attached to the cam holder 1.
It is slidably fitted into a cylindrical hole 12c as a mounting hole formed in 2. This cylindrical hole 12c is the first
As shown in Figure 1, the Rotzker armshaft 17
The holes 12a, 12 in which the large diameter portion 17a of the
These holes 12a, 1 are formed along a substantially tangential direction with respect to
2b, thereby communicating with each other.

The details of this latch adjuster 37 will be explained with reference to FIG. 9. 39 is a latch adjuster body (hereinafter abbreviated as body), and a plunger 40 is slidably fitted into a cylindrical hollow part provided in this body 39. A high pressure chamber 41 is formed along the bottom surface of the plunger 40, and the hollow part 40a of the plunger 40 is
The valve seat 40 has a check ball 42 that comes into contact with the valve seat 40c formed at the end of the passage 40b that communicates the high pressure chamber 41 with the valve seat 40.
A cage 43 that surrounds the plunger 40 with a small gap so as not to be far away from the plunger 40 is fixed to the plunger 40, and a plunger spring 44 that biases the plunger 40 is provided in the high pressure chamber 41. Communication holes 39a and 40d are provided in the body 39 and the plunger 40, respectively, for communicating the oil supply passage 45 and the hollow portion 40a of the plunger 40. The head 40e of the plunger 40 has a cylindrical shape, and a cap 46 having an outer diameter substantially the same as the outer diameter of the body 39 and a flat upper surface 46a is detachably attached to the head 40e. It will be done.

The body 39 and the cap 46 constituting the latch adjuster 37 have an outer diameter that corresponds to the cylindrical hole 12 formed in the cam holder 12.
When the body 39 and the cap 46 are fitted into the cylindrical hole 12c, the outer circumferential surfaces of the body 39 and the cap 46 are brought into sliding contact with the inner circumferential surface of the cylindrical hole 12c. A portion or a portion of the cap 46 is connected to the cylindrical hole 12c and the hole 12.
This hole 12a, 12 from the overlapped part with a, 12b
It is designed so that it can be protruded into the inside of b.

Large diameter portion 17 of the Rocker arm shaft 17
An engagement recess 17e with which the latch adjuster 37 engages and an engagement recess 17f with which an auxiliary return pin 52 (described later) engages are formed in a. The engaging recesses 17e and 17f are machined with a bottom-edge milling cutter 48 as shown in FIG. 6, and have a cylindrical surface (partially thereof) and a flat bottom surface.

The arrangement relationship between the lock adjuster 37, the rocker arm shaft 17, and the rocker arm 18 will be explained with reference to FIGS. 10 and 11.
Latch adjuster 37 (A) that engages with the rocker arm shaft 17 (A) of the side rocker arm 18 (A)
In this case, the plunger head 40e side is connected to the large diameter portion 17 of the rocker arm shaft 17(A) via the cap 46.
The rocker arm shaft 1 of the rocker arm 18 (B) on the exhaust valve 27 side engages with the engagement recess 17e of a.
7(B), the bottom 39b side of the body 39 engages with the engagement recess 17e. Note that the vertical direction in FIG. 10 corresponds to the vertical direction of the motorcycle. In both of the latch adjusters 37(A) and 37(B), the high pressure chamber 41 is located below the plunger 40, so there is no problem of oil in the high pressure chamber 41 flowing out. Note that the cap 46 is not attached to the plunger head 40e of the exhaust valve side lash adjuster 37(B), and the flat upper surface of the plunger head 40e directly contacts the plug 47. Since the contact is plane-to-plane, there is less wear and more durability than with conventional spherical plunger heads.

Further, the auxiliary return pin 52 is attached to the cam holder 1.
It is inserted into the cylindrical holes 53 (4 locations) drilled in 2,
The engaging recess 17 of the Rocker arm shaft 17
The tip contacts f and is biased toward the rocker arm shaft 17 by a spring 55 held by a bolt 54. This auxiliary return pin 52 is used when the plunger 40 of the latch adjuster 37 returns after sinking.
It provides the force to rotate the body and assists in its return.

Further, 49 is a chamber filled with oil supplied from an oil pump (not shown). 50 is the lid of this chamber 49 and is fixed with bolts 51. Oil flows from this chamber 49 to the passage 45.
through the communication hole 39a of the latch adjuster 37,
It leads to 40d.

Next, the operation of the above-mentioned valve train mechanism will be explained.

When the cam 15 rotates, the rocker arm 18 swings about the axis _O2 of the eccentric rocker arm support portion 17c of the rocker arm shaft 17, thereby opening and closing the valves 26 and 27. In this case, the rotation of the rocker arm shaft 17 is restrained by the lash adjuster 37 that engages with the engagement recess 17e, but the restraint by the lash adjuster 37 is due to the static pressure of the oil in the high pressure chamber 41. Because it is a so-called elastic restraint due to reaction force, and
Since the axis _O2 of the Rocker arm support portion 17c is eccentric, the center of rotation of the Rocker arm 18 can be slightly moved by the slight rotation of the Rocker arm shaft 17, resulting in a quiet zero latching system that always keeps the valve mechanism at zero clearance. Operation and maintenance free can be achieved.

In the above operation, regarding the intake valve 26 side,
Engagement recess 17e of Rotsuker arm shaft 17(A)
Plunger head 4 of latch adjuster 37 (A)
The cap 46 of Oe makes contact. Since this contact is made on the flat upper surface 46a of the cap 46, it has a sufficient contact surface, unlike the contact between the spherical plunger head 4b and the spherical engagement recess 1c shown in FIG. This improves durability and reliability in terms of wear. Further, since the contact between the cap 46 and the engagement recess 17e is a line contact between the upper surface 46a of the cap 46 and the edge of the engagement recess 17e, it is different from point contact as in the conventional example shown in FIG. Surface pressure can be reduced. Moreover, no load is applied to the plunger 40 in a direction perpendicular to its sliding direction, so that the lash adjuster 37 operates smoothly and its durability and reliability are improved.

Further, the positioning of the rocker arm shaft 17 in the length direction is determined by the outer periphery of the body 39 of the latch adjuster 37 on the exhaust valve 27 side.
On the side, it is performed by the outer periphery of the body 39, and
Each body 3 that engages with the cylindrical surface of the engagement recess 17e
Since the outer diameters of cap 9 and cap 46 are the same,
The engagement recess 17e having the same shape is sufficient, and there is no need to manufacture several types of rocker arm shafts each having an engagement recess corresponding to the plunger head and body, resulting in cost reduction.

Furthermore, since the outer peripheral surfaces of the body 39 and the cap 46 are in sliding contact with the inner peripheral surface of the cylindrical hole 12c of the cam holder 12, even if an external force is applied in a direction perpendicular to the sliding direction of the plunger 40, the body 39 and the cap 46 are supported by the inner peripheral surface of the cylindrical hole 12c, and as a result, there is no possibility that the body 39 and the plunger 40 will fall down.

Therefore, from this point as well, the reliability of operation, durability, etc. can be improved.

As explained above, according to the hydraulic lash adjuster of the present invention, a cap having an outer diameter substantially the same as the outer diameter of the lash adjuster body and a flat upper surface is attached to the head of the plunger. Since the lash adjuster body and the cap are removably mounted and inserted into the mounting hole formed in the mounting member, and the outer peripheral surfaces of the lash adjuster body and cap are slidably contacted with the inner periphery of the mounting hole, the lash adjuster The contact at the abutting portion with other members of the valve mechanism is in the form of a plane or a straight line orthogonal to the sliding direction of the plunger, suppressing the occurrence of wear at this contact portion, and also making the plunger more flexible in the sliding direction. Or, even if such a load is applied, this load is transmitted through the outer circumferential surface of the body and cap to the inner circumferential surface of the mounting hole of the mounting member. The support prevents the plunger and body from falling down, increasing the durability of the hydraulic latch adjuster.
It has various excellent effects such as improving reliability and reducing costs since it is not necessary to make several types of rocker arm shafts.

[Brief explanation of drawings]

Figures 1 to 4 show a conventional hydraulic lash adjuster, with Figure 1 being a front view of the rocker arm shaft, Figure 2 being a sectional view of the main parts of the valve mechanism, Figures 3 and 4. Fig. 4 is an enlarged view of the main parts in Fig. 2, Fig. 5 and the following show an embodiment of the present invention, Fig. 5 is an exploded perspective view of the cylinder head of a horizontally opposed engine, and Fig. An exploded perspective view of the cam holder part, Figures 7A and 7B are front and side views of the Rocker arm shaft, respectively, Figure 8 is an explanatory diagram of the Rocker arm shaft arrangement, and Figure 9 is the hydraulic latch adjuster. 10 is a sectional view of the main part of the valve mechanism, Fig. 11 A and B are enlarged views of the main part in Fig. 10, and Fig. 12 is a sectional view of the main part of the valve mechanism.
0 is a view taken along arrow A in FIG. 11... Cylinder head, 12... Cam holder, 15... Camshaft, 17... Rocker arm shaft, 17a... Large diameter part, 17b... Small diameter part, 17c... Rocker arm support part, 17e
...Engagement recess, 18...Rotzker arm, 26...
...Intake valve, 27...Exhaust valve, 37...Lush adjuster, 38...Collar, 39...Lush adjuster body, 40...Plunger, 40e...
...Head, 41...High pressure chamber, 42...Check ball, 44...Plunger spring, 46...Cap, 46a...Top surface.

Claims (1)

[Claims] 1. A cap having an outer diameter approximately the same as the outer diameter of the rush adjuster body and having a flat upper surface is removably attached to the head of the plunger, and the cap is inserted into the mounting hole formed in the mounting member. 1. A hydraulic lash adjuster, characterized in that the lash adjuster body and the cap are inserted so that the outer circumferential surfaces of the latch adjuster body and the cap slide into contact with the inner circumferential surface of a mounting hole.